Threading-tool.



. 881,406 H. JANSEN.

THREADING TOOL.

APPLICATION TILED MAY 20, 1907.

PATENTBD MAR, 1Q, 1908.

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UNITED STATES PATENT OFFICE.

HENRY JANSEN, OF CHICAGO, ILLINOIS.

THREADING-TOOL.

Specification of Letters Patent.

Patented March 10, 1908.

Application filed May 20, 1907.. Serial No. 374,619.

particularlyto improvements in the manner and means of forming and securing the cutting teeth of these tools. In the common forms of dies and taps at present in use, the radially projecting teeth are formed integral with the body of thedie or tap, which construction has two leading disadvantages. In the first place, it is difficult to form the cutting teeth accurately and on a true pitch line and with sharp edges; and in the second place, and especially in the case of threading dies, when the teeth become dull or worn to a point where they are ineffective, the entire tool is discarded, owing to the difliculty and pracltical impossibili ty of resharpening the teet My invention has for its leading object to obviate the aforementioned difficulties, and as 21 consequence cheapen the cost of these too s.

A further object of the invention is to provide a tool of superior efliciency and accuracy. These objects are attained by the present invention, which has for its leading novel feature the provision of teeth that are separable from the body of the die or tap and are capable, when worn or dulled, of being removed, resharpened, and accurately replaced in the tool. These teeth are rigidly secured in slots or similar openings formed in the body of the tool by pins or keys which may be readily withdrawn to permit the removal of the tool for resharpening.

In the accompanying drawings I have illustrated the principle of my invention as embodied in a threading die adapted to cut external screw threads on bolts, pipes and the like; but it will be understood that the principle of the'invention is equally applicable to the reverse form of tool known as a threading tap, adapted for the cutting. of internal threads, andin itsbroad aspects the invertion relates to and covers a tap as well as a 1e.

Referring to the drawings,Fi ure 1 is a plan viewof the rear or back side-o a threading die embodying one form of the invention= Fig. 2 is a cross-secti on al view on the line 2-2 of Fig. 1 looking in the directionindicated by the arrows. Fig. 3 is a front or face view of the same die. Figs. 4, 5 and .6 are views corresponding with Figs. 1, 2 and 3, respectively, of a modified form of die embodying my invention, Fig- 5 being a View on the secv tionline 55 of Fig. 4. Figs. 7 and 8 are detail side and edge views, respectively, of an individual cutting tooth; and Fig. 9 is a diagrammatic view illustrating the relative arrangement and pitch line relations of the flour rows or series of teeth employed in the 1e.

Referring first to Figs. 1, 2 and 3, 10 designates the body of the die, herein shown as a plain rectangular metal block having parallel fiat sides and containing a central circular opening 1 1 formed therethrough, adapted. for

the passage of the object or article to be threaded by the tool. The four corner portions of the die-body are formed with radially directed slots extending some distance inwardly from the margin of the circular opening 11. In these slots are seated and snugly fitted corres onding stacks or series of individual threa ing teeth shown at 12, one of said teeth being illustrated in detail in Figs. 7 and 8. The teeth are provided on one or both edges with notches, such as are shown at 13 in Figs. 7 and8 adapted for the reception of pins or keys 14 whereby to lock the teeth against endwise displacement relatively to their containing slots or seats; the teeth shown in Figs. -1, 2 and 3 having the keys applied wholly on one side, while those illustratedin Figs. 4, 5 and6 have the keys applied, one on each side. The teeth of each series or stack are confined laterally by means of corner plates 15, 16, 17 and 18 on the face thereof, and similar corner plates 19, 20, 21, and 22 on the back or reverse side thereof. 1 The corner plates are preferably,

and as herein shown, themselves equipped with the first and last teeth of each series, and, in order to secure the pitch-line arrange.

ment of the teeth and, at the same time, provide flat arallel outer surfaces or'sides on the die, the corner plates of'each series-are made of graduated thickness, and are all, exce t the thinnest of each series, inset into the ace of the die-body, as shown in Fig. 2, wherein it will be seen that. the thinnest plate block, and carries an initial tooth 18.

tooth 16 thicker than the corner plate 16 and is inset 15 of the first series rests directly upon the face of the die-block and is provided with a narrow initial tooth ]5 the next thinnest plate 16 is slightly inset in the face of the block and is provided with an integral'initial The corner plate 17 is slightly into the block a correspondingly greater distance and is provided with an initial cutting tooth 17; while the remaining corner plate 18 is of substantially the full thickness of a cutting tooth, and is inset deepest into 1%16 T 1e corner plates 19, 20, 21 and 22 on the back of the die-block are similarly formed but illversely arranged. That is to say, the thickest corner plate 22 of the back series lies opposite the thinnest corner plate 15 of the front series, and vice versa; these back corner plates being provided with corresponding final cutting teeth 19 20, 21 and 22 respectively. In this manner the teeth of the successively operating rows are slightly offset relatively to each other longitudinally of the bore of the tool as is required to locate them in the proper pitch-line. In order to effect the introduction and initial grip or bite of the tool upon the pipe, bolt, or other article to be threaded, the first two or three teeth of each series on the face or entering side of the die are ground down or beveled off so as to relatively enlarge the diameter of the entering face of the die this formation of the teeth being indicated in Figs. 2 and 3, wherein the teeth 15, 16 17 and 18* are shortest; the next teeth 12 are somewhat longer than the initial teeth, but shorter 5 than the full teeth 12; while the third tooth of each series is of full cutting size and length.

The opposite pairs of plates on each corner of the die-block are rigidly secured to each other and to the block by suitable fastening means, preferably flat-head rivets 23, which suffice to preserve the smooth fiat surfaces of the opposlte sides of the die, and yet may be readily driven out with a suitable tool when necessary to remove the teeth.

" and 3.

tral circular opening formed therethrough;

'1 and between said plates at each of the four corners thereof I interpose a spacing and filling block 25 that is similarly slotted to register with the slots of the plate 24. In the seats thus formed by these slots are 1 packed the several series of full cutting teeth 12, as already described in connection with Figs. 1, 2 and 3 and in addition thereto, at

the ends of each series, I provide teeth of graduated thickness indicated by 26, 27, 28 and 29 on the entering side of the series, and corresponding but inversely arranged graduated teeth 26, 27, 2S and 29 on the back or reverse side of the series. This arrangement throws the full cutting teeth of the several series into proper 'piteh line with each other; and the teeth are confined laterally by plain corner plates 30 of uniform thickness applied to the outer sides of the main body or frame-plates 24, which latter, in connection with the filling and spacing blocks 25, make up the die-block or body.

The initial cutting teeth 26, 27, 2S, and 29 on the entering side of the die are made shorter, as above explained, to enlarge the diameter of the mouth of the die; and the next teeth behind said initial cutting teeth are also somewhat shortened to produce the desired tapering effect on the mouth of the die, as is well understood in dies of this character. The graduation of the initial cutting teeth as to thickness, whereby the full cutting teeth of the several series or rows are thrown into offset or pitch-line relation, is illustrated in. the diagrammatic view shown by Fig. 5), wherein the four rows or series of teeth are projected onto a plane surface, the parallelism of the sides of the die-block represented by the two series of corner plates being also illustrated therein.

The plates 24, filling blocks 25, and corner plates 30 are rigidly united preferably by means of flat-head rivets 23 countersunk in. corner plates, as hereinabove specified. It would, of course, be practicable to use, with this form of die-block, corner plates of graduated thickness carrying the initial and final teeth of each series, as described in connection with Figs. 1, 2 and 3, if desired.

It will be observed that by reason of the manner and means of forming and securing the cutting teeth of the tool as herein above described and illustrated in. the drawings, it is possible and feasible to remove the teeth from the die-block when found necessary or desirable, accurately resharpen them, and replace them, thus making the tool practically as good as new and greatly increasing its longevity. Furthermore, when one set of teeth have been used and resharp'ened until worn too short for further use, they can be replaced by new teeth without discarding the die-block or frame, the life of which latter is thus practically unlimited. The accurate pitch-line relation of the teeth can also be more readily secured where the teeth are independently formed and assembled, as in my device, than where formed integrally with the die-block.

It will be evident to those skilled in the art that other specific modes and means of, removably securing}; detachable teeth in, a threading tool of the character described will readily suggest themselves from the disclosures herein made, and hence I do not limit the invention to the particular forms shown and described, except to the extentand a series of detachable individual threading teeth seated and rigidly secured in each ofsaid slots, substantially as described.

2. A threading tool consisting of a toothholder having radial slots formed therein, a series of detachable individual threading teeth seated and rigidly secured in each of said slots, and clamp plates on one orbboth sides of said tooth-holder having integral teeth located in alinement with the individual threading teeth of each series, substantially as described.

3. A threading die consisting of a dieblock or frame having parallel flat sides and a central opening formed therethrough and further provided with a plurality of radially directed slots at their inner ends communicatin with said opening, a group of individua threading teeth seated and detachably secured in each of said slots, and clampplates applied to the opposite sides of the die-block and overlying said slots whereby to confine said teeth against lateral displacement, the clamp plates on one or both sides of said die-block having integral teeth located in alinement With the individual threadin teeth of each group substantially as descri ed.

HENRY JANSEN.

Witnesses: v

SAMUEL N. POND, FREDERICK O. GoonwrN. 

